As soon as boost comes on, Cyl. 1 Misfires?

[2FastTSiAWD]

Just like the title says. I m completely stumped. Everytime I hit past like 4lbs of boost, My car starts stuttering and bucking. I pull the plug in cyl 1 and the gap is closed. I ve replaced the coilpack, the injector in cylinder 1, the ignitor, and the injector resistor. I have a Walbro 190 coming tommorrow, although upon testing, the pum is fine. Using a noid light, the inector is only seeing signal half the time? Also, after tying plastic bags tover all of the injectors, it is spraying, althoug I can be sure if it is when I hit boost. My laptop crashed, so I cant even datalog. Please help, I can hardly drive my car!

 

[crankbender]

I am not absolutely convinced it is a fuel problem yet. Is it RPM dependent or only boost dependent. Does it start around the same boost no matter what RPM you are at. If it seems that RPM isn't a factor I would deffinately replace that plug with just a copper one (champion works fine and is cheap) and put on a new spark plug wire to test that.

If you are firing on cylinder 4 then your coil pack is good as it fires plug 1 and 4 at the same time. You have to be grounding somewhere to not spark on cylinder #1 so it looks like a broken insulator on the plug or bad plug wires. This follows with the problem only being at boost because the increase in air density, temp, etc causes the resistance across the plug to increase.

 

[2FastTSiAWD]

Sorry, forgot to mention in the post that I have changed the plug wires. Also, the plug thats in right now is the fourth one! The first time I noticed it, when i pulled the plug, it was badly melted! As for 4 not firing correctly, already thought about that too. and four is fine. Thats whats weird, it s only cylinder 1. It is boost dependant, because if I give it moderate throttle slowly, it will go up in the R's, as long as I dont get into boost. Any other ideas? I m really stumped here, and i dont have transportation until I can figure this out! Thanks.

 

[crankbender]

if you melted the plug you are lean. Try pulling the fuel rail and checking if it is clogged.

Other than that it is possible that you are not getting enough flow. How long has it been since you replaced your fuel filter?

Do not run the car like that....if you are melting plugs what do you think you are doing to those pistons and that aluminum head?

 

[2FastTSiAWD]

Checkedthe fuel rail already, it isnt plugged. The fuel filter was changed about 10k ago. Is that too long? I havent been driving the car, the four plugs have been in the last week. Any time that the gap has closed on a plug was from a VERY easy test run after fixing something to see if it cured thte problem. I m going to change the fuel filter tomorrow. I also forgot to tell how this came on. I had jsut installed a new dejon tool uicp, and intake pipe. I took it out for a run, got on it, and a coupling blew. Fixed the coupling, and this has been the result, is there any direct connection? I ve already swappedthe intake pipe back to the stock one, but nothing changed, I ve been thinking about changing the uivp, but I jsut dont see how that could be the problem. Any other things to try? Thanks for all the input thus far.

 

[LightningGSX]

Swap the #1 injector with one of the others, if the problem moves to that cylinder, replace or clean the injector.

 

[2FastTSiAWD]

For anyone that might come acrossed this problem in the future. Check the O2 snesor, thats what did it to mine.

 

[Mitsuturbo]

If you melted a spark plug.. you've got much more to worry about than some bucking under boost. There's a STRONG possibility that you've burned a valve or a piston. You've run WAAAY too lean for FAR too long.
You don't have an EGT gauge, do you?